JP5698347B2 - Cell balance device - Google Patents

Description

  The present invention relates to a cell balance circuit and a cell balance device including a plurality of cell balance circuits.

  Conventionally, when a plurality of secondary batteries are used, it is necessary to perform cell balance to equalize the charging voltages of the plurality of secondary batteries. Therefore, there is a case where one resistor is connected in parallel to each of the plurality of secondary batteries. According to this, since the secondary battery having a higher charging voltage than the others can be discharged by the resistance connected in parallel, the charging voltages of the plurality of secondary batteries can be made uniform.

  However, when resistors are connected in parallel as described above, power loss increases due to discharge at the resistors. Therefore, a circuit shown in Patent Document 1 and a circuit shown in Patent Document 2 have been proposed.

JP 2010-288447 A JP 2004-88878 A

  The circuit disclosed in Patent Document 1 uses a diode to equalize the charging voltage. Here, since the forward voltage of the diode changes according to the temperature, there is a possibility that the charging voltages of the plurality of secondary batteries cannot be equalized accurately. Further, even if the change according to the temperature of the forward voltage of the diode described above can be ignored, the circuit shown in Patent Document 1 makes the charge voltage uniform only when the secondary battery is charged. When the secondary battery was discharged, the charging voltage became non-uniform, and the cell balance could not be stabilized.

  On the other hand, in the circuit shown in Patent Document 2, it is necessary to monitor the charging voltages of the plurality of secondary batteries. For this reason, an element or a circuit for monitoring the charging voltage of the secondary battery is required, which has been an obstacle to cost reduction and miniaturization.

  In addition, the circuit shown in Patent Document 1 and the circuit shown in Patent Document 2 are temporarily deteriorated because cell balancing is performed after a difference occurs in the charging voltages of a plurality of secondary batteries. There was a risk that the secondary battery would deteriorate due to reaching the region.

  In view of the above-described problems, the present invention provides a cell capable of equalizing the charging voltage during charging and discharging of the secondary battery while realizing cost reduction and downsizing and suppression of deterioration of the secondary battery. An object is to provide a balance circuit and a cell balance device.

The present invention proposes the following items in order to solve the above-described problems.
(1) The present invention charges each of the first secondary battery (for example, equivalent to the secondary battery BT1 in FIG. 5) and the second secondary battery (for example, equivalent to the secondary battery BT2 in FIG. 5). A cell balance circuit (for example, equivalent to the cell balance circuit BB in FIG. 5) for equalizing the voltage, and a first winding (for example, the first winding in FIG. 5) paired with the first secondary battery. 1 (corresponding to the first winding Wa) and a second winding (for example, corresponding to the second winding Wb in FIG. 5) provided in pairs with the second secondary battery (for example, , Corresponding to the transformer T in FIG. 5) and switching means for controlling whether or not the charging voltage of the first secondary battery is applied to the first winding, the switching means comprising: 1 switch (for example, equivalent to the switch Sa in FIG. 5) and the second switch (for example, the switch in FIG. 5). Hb Sb), a third switch (for example, equivalent to the switch Sc in FIG. 5), and a fourth switch (for example, equivalent to the switch Sd in FIG. 5), and the other end of the first winding And one end of the second winding is connected to the other end of the first secondary battery, and is connected to one end of the second secondary battery, and one end of the first winding. Is provided so as to be connectable to one end of the first secondary battery via the first switch and to be connectable to the other end of the second secondary battery via the second switch. The other end of the second winding is provided to be connectable to one end of the first secondary battery via the third switch, and the second winding via the fourth switch. Provided to be connected to the other end of the secondary battery, the first switch and the fourth switch; A cell balance circuit characterized in that the second switch and the third switch are alternately turned on when the first secondary battery and the second secondary battery are charged and discharged. Has proposed.

  According to the present invention, the transformer and the switching means are provided in the cell balance circuit that equalizes the charging voltages of the first secondary battery and the second secondary battery. The transformer was provided with a first winding paired with the first secondary battery, and a second winding paired with the second secondary battery. In addition, the switching means controls whether or not the charging voltage of the first secondary battery is applied to the first winding.

  According to the invention, the switching means includes the first switch, the second switch, the third switch, and the fourth switch. Then, the other end of the first winding and one end of the second winding were connected to the other end of the first secondary battery and to one end of the second secondary battery. Further, one end of the first winding is provided so as to be connectable to one end of the first secondary battery via the first switch, and to the other end of the second secondary battery via the second switch. Provided to be connectable. The other end of the second winding is provided so as to be connectable to one end of the first secondary battery via the third switch, and the other end of the second secondary battery is provided via the fourth switch. It was provided so that it could be connected to.

  Therefore, when the first switch and the fourth switch are turned on, and the second switch and the third switch are turned off, the first secondary battery is connected to both ends of the first winding. Both ends can be connected, and both ends of the second secondary battery can be connected to both ends of the second winding. According to this, the charging voltage of the first secondary battery is applied to the first winding, and the charging voltage of the second secondary battery is applied to the second winding.

  In addition, when the first switch and the fourth switch are turned off and the second switch and the third switch are turned on, both ends of the second secondary battery are connected to both ends of the first winding. And both ends of the first secondary battery can be connected to both ends of the second winding. According to this, the charging voltage of the second secondary battery is applied to the first winding, and the charging voltage of the first secondary battery is applied to the second winding.

When the charging voltage of the first secondary battery is applied to the first winding, a magnetic flux is generated in the first winding, and this magnetic flux penetrates the second winding. When this magnetic flux is Φ _B and the number of turns of the second winding is N, an electromotive force ε shown in the following equation (1) is generated in the second winding.

  Here, the magnetic flux generated in the first winding changes according to the voltage applied to the first winding. For this reason, the electromotive force generated in the second winding changes according to the charging voltage of the first secondary battery.

  Also in the second winding, similarly to the first winding described above, a magnetic flux is generated when the charging voltage of the second secondary battery is applied, and this magnetic flux penetrates the first winding. An electromotive force similar to that shown in the above-described equation (1) is generated in the first winding. And the electromotive force which generate | occur | produces in a 1st coil | winding will change according to the charging voltage of a 2nd secondary battery.

  Here, it is assumed that the number of turns of the first winding is equal to the number of turns of the second winding, and the charging voltage of the second secondary battery is applied to the second winding. Further, the charging voltage of the first secondary battery is VBT1, the charging voltage of the second secondary battery is VBT2, the resistance component of the first winding is RW1, and the resistance component of the second winding is RW2. Then, the current IW1 flowing through the first winding is expressed as the following expression (2), and the current IW2 flowing through the second winding is expressed as the following expression (3). Become.

  When the charging voltage of the first secondary battery and the charging voltage of the second secondary battery are equal, the current does not flow through the first winding and the above-described equation (2). Since current does not flow through the second winding as in the expression (3), current does not flow through the first secondary battery and the second secondary battery.

  On the other hand, when the charging voltage of the first secondary battery is lower than the charging voltage of the second secondary battery, the charging voltage of the first secondary battery is equal to the charging voltage of the second secondary battery. Until this time, the current determined by the above equation (2) flows from the first winding to the first secondary battery, and the first secondary battery is charged. Further, until the charging voltage of the first secondary battery becomes equal to the charging voltage of the second secondary battery, the current determined by the above equation (3) is transferred from the second secondary battery to the second winding. Then, the second secondary battery is discharged.

  Further, when the charging voltage of the first secondary battery is higher than the charging voltage of the second secondary battery, the charging voltage of the first secondary battery is equal to the charging voltage of the second secondary battery. Until this time, the current determined by the above equation (2) flows from the first secondary battery to the first winding, and the first secondary battery is discharged. Further, until the charging voltage of the first secondary battery becomes equal to the charging voltage of the second secondary battery, the current determined by the above equation (3) is transferred from the second winding to the second secondary battery. Then, the second secondary battery is charged.

  As described above, the charging voltage of the first secondary battery is equal to the charging voltage of the second secondary battery. For this reason, since the diode required by the circuit shown in the above-mentioned Patent Document 1 is not used, the charging voltage is accurately equalized for the first secondary battery and the second secondary battery. Can do.

  In addition, the switching means can be operated without detecting the charging voltage of the first secondary battery or the second secondary battery. For this reason, it becomes unnecessary to monitor the charging voltage of the first secondary battery or the second secondary battery, so that the cost and size of the cell balance circuit can be reduced.

  Moreover, when one resistor is connected in parallel to each of the plurality of secondary batteries as described above, the current that can be passed through these secondary batteries is limited by these resistors. On the other hand, in the present invention, the cell balance circuit is provided with a transformer but no resistor. Since the resistance values of the first winding and the second winding provided in the transformer are significantly smaller than the resistance value of the resistance, the current limited by the transformer is compared with the current limited by the resistance. Significantly smaller. Therefore, the first secondary battery and the second secondary battery are compared with the case where one resistor is connected in parallel to each of the first secondary battery and the second secondary battery as described above. The current that can be supplied to the battery can be increased.

  Here, secondary batteries such as the first secondary battery and the second secondary battery output DC power. Therefore, if the first switch and the fourth switch are left in the on state, or if the second switch and the third switch are left in the on state, the first winding and the second switch The transformer having the windings of saturates.

  Therefore, according to the present invention, the first switch and the fourth switch, and the second switch and the third switch are used when the first secondary battery and the second secondary battery are charged and discharged. It was decided to turn it on alternately. For this reason, every time the first switch, the second switch, the third switch, and the fourth switch are turned on / off, the polarity of the voltage at one end with respect to the other end of the first winding is reversed. At the same time, the polarity of the voltage at one end with respect to the other end of the second winding is also reversed. According to this, it is possible to prevent the transformer from being saturated.

  Further, according to the present invention, as described above, the first switch and the fourth switch, the second switch and the third switch are connected to the first secondary battery and the second secondary battery. It was decided to turn on alternately during charging and discharging. Therefore, when charging and discharging the first secondary battery and the second secondary battery, the charging voltage of the first secondary battery is applied to the first winding by the switching means, and the second The charging voltage of the secondary battery can be applied to the second winding. Therefore, the charging voltages of the first secondary battery and the second secondary battery can be accurately equalized not only when charging the first secondary battery and the second secondary battery but also when discharging. The cell balance can be stabilized. In addition, since it is possible to suppress a difference in charging voltage between the first secondary battery and the second secondary battery during charging and discharging of the first secondary battery and the second secondary battery, It is possible to prevent the first secondary battery and the second secondary battery from temporarily reaching the deterioration region, and to suppress the deterioration of the first secondary battery and the second secondary battery.

  (2) The present invention proposes a cell balance circuit according to (1), wherein the number of turns of the first winding is equal to the number of turns of the second winding. Yes.

  According to the present invention, in the cell balance circuit of (1), the number of turns of the first winding is made equal to the number of turns of the second winding. For this reason, the effect similar to the effect mentioned above can be produced.

  (3) The present invention proposes a cell balance circuit in which the cell balance circuit of (1) or (2) is provided integrally with the first secondary battery.

  According to the present invention, in the cell balance circuit of (1) or (2), the cell balance circuit and the first secondary battery are integrally provided. For this reason, the apparatus provided with a cell balance circuit and a 1st secondary battery can be reduced in size.

(4) In the cell balance circuit according to any one of (1) to (3), the present invention provides that the switching unit forms a non-resonant circuit (for example, see FIGS. 1 to 7, 9, and 10 ). A cell balance circuit is proposed.

  According to the present invention, in the cell balance circuit according to any one of (1) to (3), the switching means forms a non-resonant converter. For this reason, the effect similar to the effect mentioned above can be show | played by switching appropriately the switch element provided in a non-resonance type | mold converter.

  (5) The present invention provides the cell balance circuit according to any one of (1) to (4), wherein the first winding and the second winding are wound around an iron core. A balance circuit is proposed.

  According to the present invention, in the cell balance circuit according to any one of (1) to (4), the first winding and the second winding are wound around the iron core. Therefore, the first winding and the second winding are not wound around the iron core, that is, the first winding and the second winding are compared with the case where the first winding and the second winding are empty. Since the magnetic flux generated by the wire and the second winding can be stabilized, the cell balance can be stabilized with higher accuracy.

  (6) The present invention relates to a cell balance device (for example, equivalent to the cell balance device 1 of FIG. 6) including a plurality of the cell balance circuits of any one of (1) to (5). The switching of the second switch, the third switch, and the fourth switch is asynchronous among each of the plurality of cell balance circuits.

  Here, when a plurality of the cell balance circuits of any one of (1) to (5) are provided, as described above, the first secondary batteries provided in pairs in each of the plurality of cell balance circuits. In addition, the charging voltage of the second secondary battery can be made uniform. For this reason, it is not necessary to synchronize the switching of the first switch, the second switch, the third switch, and the fourth switch among the plurality of cell balance circuits.

  So, according to this invention, in a cell balance apparatus provided with two or more cell balance circuits in any one of (1)-(5), a 1st switch, a 2nd switch, a 3rd switch, and a 4th switch The switching is asynchronous between each of the plurality of cell balance circuits.

  For this reason, in each of the plurality of cell balance circuits, the first switch, the second switch, the third switch, and the fourth switch can be switched independently. Therefore, since it is not necessary to synchronize the switching of these switches among a plurality of cell balance circuits, switching control can be facilitated, and the design of the cell balance device can be facilitated.

  (7) The present invention charges each of the first secondary battery (for example, equivalent to the secondary battery BT1 in FIG. 12) and the second secondary battery (for example, equivalent to the secondary battery BT2 in FIG. 12). A cell balance circuit for equalizing the voltage (for example, equivalent to the cell balance circuit KK of FIG. 12), and a first primary winding (for example, FIG. 12) provided in a pair with the first secondary battery. And a first transformer having a first secondary winding (e.g., equivalent to the secondary winding W12 in FIG. 12) (e.g., equivalent to the transformer T1 in FIG. 12); A second primary winding (for example, equivalent to the primary winding W21 in FIG. 12) and a second secondary winding (for example, the secondary in FIG. 12) provided in pairs with the second secondary battery. A second transformer having a winding W22 (e.g., corresponding to the transformer T2 in FIG. 12); First switching means (for example, corresponding to the switch SW1 in FIG. 12) for controlling whether or not the charging voltage of the secondary battery is applied to the first primary winding, and the second secondary battery Second charging means (for example, corresponding to the switch SW2 in FIG. 12) for controlling whether or not to apply the charging voltage to the second primary winding, the first primary winding. And the number of turns of the first secondary winding are different, the number of turns of the first primary winding is equal to the number of turns of the second primary winding, and the first 2 The number of turns of the secondary winding is equal to the number of turns of the second secondary winding, the first secondary winding and the second secondary winding are connected in parallel, and the first switching The means connects one end of the first secondary battery and one end of the first primary winding, and connects the first secondary battery. A first procedure for connecting the other end of the pond and the other end of the first primary winding, one end of the first secondary battery, and the other end of the first primary winding, , And a second procedure for connecting the other end of the first secondary battery and one end of the first primary winding, and the second switching means One end of the second secondary battery is connected to one end of the second primary winding, the other end of the second secondary battery, and the other end of the second primary winding. And connecting one end of the second secondary battery and the other end of the second primary winding, and the other end of the second secondary battery. A cell balance circuit characterized by performing a fourth procedure of connecting one end of the second primary winding is proposed.

  According to this invention, the first transformer, the second transformer, and the first switching means are added to the cell balance circuit that equalizes the charging voltages of the first secondary battery and the second secondary battery. Provided. The first transformer was provided with a first primary winding and a first secondary winding paired with the first secondary battery. The second transformer was provided with a second primary winding and a second secondary winding in pairs with the second secondary battery. Further, the first switching means controls whether or not the charging voltage of the first secondary battery is applied to the first primary winding. For this reason, the charging voltage of the first secondary battery can be applied to the first primary winding by the first switching means.

When a charging voltage of the first secondary battery is applied to the first primary winding, a magnetic flux is generated in the first primary winding, and this magnetic flux passes through the first secondary winding. Become. When this magnetic flux is Φ _B and the first secondary winding is N, the electromotive force ε shown in the above equation (1) is generated in the first secondary winding.

  Here, the magnetic flux generated in the first primary winding changes according to the voltage applied to the first primary winding. For this reason, the electromotive force generated in the first secondary winding changes according to the charging voltage of the first secondary battery.

In the second primary winding, as in the first primary winding of the above, the charging voltage of the second secondary battery is applied magnetic flux is generated, the secondary magnetic flux is second In order to penetrate the winding, an electromotive force similar to that shown in the above formula (1) is generated in the second secondary winding. And the electromotive force which generate | occur | produces in a 2nd secondary winding will change according to the charging voltage of a 2nd secondary battery.

  According to the present invention, the number of turns of the first primary winding and the number of turns of the first secondary winding are made different, and the first primary winding and the second primary winding The number of turns of each was made equal, and the number of turns of each of the first secondary winding and the second secondary winding was made equal. For this reason, the turns ratio of the first primary winding and the first secondary winding is equal to the turns ratio of the second primary winding and the second secondary winding. The ratio of the winding voltage of the primary winding to the winding voltage of the first secondary winding is the ratio of the winding voltage of the second primary winding to the winding of the second secondary winding. It becomes equal to the ratio of the line voltage. Therefore, the ratio of the charging voltage of the first secondary battery and the winding voltage of the first secondary winding is the ratio of the charging voltage of the second secondary battery and the winding of the second secondary winding. It becomes equal to the ratio of the line voltage. Therefore, the ratio of the charging voltage of the first secondary battery to the charging voltage of the second secondary battery is determined by the winding voltage of the first secondary winding and the winding of the second secondary winding. It becomes equal to the ratio of the line voltage.

  According to the above, when the charging voltage of the first secondary battery and the charging voltage of the second secondary battery are equal, the winding voltage of the first secondary winding and the second secondary winding The winding voltage of the wire is equal. On the other hand, when the charging voltage of the first secondary battery is lower than the charging voltage of the second secondary battery, the winding voltage of the first secondary winding is the winding voltage of the second secondary winding. Lower. When the charging voltage of the first secondary battery is higher than the charging voltage of the second secondary battery, the winding voltage of the first secondary winding is the winding voltage of the second secondary winding. Get higher.

  Moreover, according to this invention, the 1st secondary winding and the 2nd secondary winding were connected in parallel. For this reason, the winding voltage of the first secondary winding and the winding voltage of the second secondary winding tend to be equal.

  Therefore, when the charging voltage of the first secondary battery and the charging voltage of the second secondary battery are equal, the winding voltage of the first secondary winding and the second 2 Since the winding voltage of the secondary winding becomes equal, no current flows between the first secondary winding and the second secondary winding. Therefore, no current flows through the first secondary battery and the second secondary battery.

  On the other hand, when the charging voltage of the first secondary battery is lower than the charging voltage of the second secondary battery, the winding voltage of the first secondary winding is the second secondary winding as described above. Until the winding voltage of the first secondary winding and the winding voltage of the second secondary winding are equal, that is, the charging voltage of the first secondary battery. A current flows from the second secondary winding to the first secondary winding until the charging voltage of the second secondary battery becomes equal. Therefore, current flows from the first primary winding to the first secondary battery until the charging voltage of the first secondary battery becomes equal to the charging voltage of the second secondary battery, The secondary battery is charged. Further, current flows from the second secondary battery to the second primary winding until the charging voltage of the first secondary battery becomes equal to the charging voltage of the second secondary battery, and the second secondary battery The secondary battery is discharged.

  When the charging voltage of the first secondary battery is higher than the charging voltage of the second secondary battery, the winding voltage of the first secondary winding is the second secondary winding as described above. Since the winding voltage of the first secondary winding and the winding voltage of the second secondary winding are equal, that is, the charging voltage of the first secondary battery A current flows from the first secondary winding to the second secondary winding until the charging voltage of the second secondary battery becomes equal. Therefore, current flows from the first secondary battery to the first primary winding until the charging voltage of the first secondary battery becomes equal to the charging voltage of the second secondary battery, and the first The secondary battery is discharged. Further, current flows from the second primary winding to the second secondary battery until the charging voltage of the first secondary battery becomes equal to the charging voltage of the second secondary battery, and the second secondary battery The secondary battery is charged.

  As described above, the charging voltage of the first secondary battery is equal to the charging voltage of the second secondary battery. For this reason, since the diode required by the circuit shown in the above-mentioned Patent Document 1 is not used, the charging voltage is accurately equalized for the first secondary battery and the second secondary battery. Can do.

  In addition, when charging and discharging the first secondary battery and the second secondary battery, the charging voltage of the first secondary battery is applied to the first primary winding by the first switching means. By applying the charging voltage of the second secondary battery to the second primary winding, the first secondary battery and the second secondary battery can be charged not only during charging but also during discharging. The charging voltages of the secondary battery and the second secondary battery can be made uniform accurately, and the cell balance can be stabilized.

  In addition, the first switching means can be operated without monitoring the charging voltage of the first secondary battery or the second secondary battery. For this reason, it becomes unnecessary to monitor the charging voltage of the first secondary battery or the second secondary battery, so that the cost and size of the cell balance circuit can be reduced.

  In addition, the charging voltage of the first secondary battery and the second secondary battery is set to the first primary volume as described above when charging and discharging the first secondary battery and the second secondary battery, respectively. By applying the voltage to the wire and the second primary winding, it is possible to suppress the difference between the charging voltages of the first secondary battery and the second secondary battery. For this reason, it is possible to prevent the first secondary battery and the second secondary battery from being deteriorated by temporarily preventing the deterioration area.

  Moreover, when one resistor is connected in parallel to each of the plurality of secondary batteries as described above, the current that can be passed through these secondary batteries is limited by these resistors. On the other hand, in the present invention, the cell balance circuit is provided with the first transformer and the second transformer but not with the resistor. Resistance values of the first primary winding and the first secondary winding provided in the first transformer, and the second primary winding and the second secondary winding provided in the second transformer Since the resistance value of the line is significantly smaller than the resistance value of the resistor, the current limited by the first transformer and the second transformer is significantly smaller than the current limited by the resistance. Therefore, the first secondary battery and the second secondary battery are compared with the case where one resistor is connected in parallel to each of the first secondary battery and the second secondary battery as described above. The current that can be supplied to the battery can be increased.

  Here, secondary batteries such as the first secondary battery and the second secondary battery output DC power. For this reason, the charging voltage of the first secondary battery simply continues to be applied to the first primary winding, or the charging voltage of the second secondary battery simply continues to be applied to the second primary winding. Then, the first transformer and the second transformer are saturated.

  Therefore, according to the present invention, the first procedure and the second procedure are performed by the first switching means, and the third procedure and the fourth procedure are performed by the second switching means. In the first procedure, one end of the first secondary battery and one end of the first primary winding are connected, and the other end of the first secondary battery and the first primary winding are connected. In the second procedure, one end of the first secondary battery is connected to the other end of the first primary winding, and the other end of the first secondary battery is connected to the other end of the first secondary battery. The first primary winding is connected to one end of the first primary winding. In the third procedure, one end of the second secondary battery and one end of the second primary winding are connected, the other end of the second secondary battery, and the second primary winding. In the fourth procedure, one end of the second secondary battery and the other end of the second primary winding are connected in addition to the other end of the second secondary battery. The end is connected to one end of the second primary winding.

  According to this, every time switching from the first procedure to the second procedure or switching from the second procedure to the first procedure, the polarity of the voltage at one end with respect to the other end of the first primary winding is changed. It will be reversed. Also, every time switching from the third procedure to the fourth procedure or from the fourth procedure to the third procedure, the polarity of the voltage at one end with respect to the other end of the second primary winding is reversed. become. For this reason, it is possible to prevent the first transformer and the second transformer from being saturated.

  (8) In the cell balance circuit of (7), the present invention relates to a DC source that outputs a DC voltage (for example, equivalent to the DC source 31 of FIG. 14), and the output voltage of the DC source is the first secondary voltage. A cell balance circuit characterized by comprising third switching means (for example, corresponding to the switch SW3 in FIG. 14) for controlling whether or not to apply to the winding is proposed.

  According to this invention, in the cell balance circuit of (7), the third switching that controls whether or not the output voltage of the DC source is applied to the first secondary winding, and the DC source that outputs the DC voltage. Means. Therefore, when the output voltage of the DC source is applied to the first secondary winding by the third switching means, the output voltage of the DC source and the winding voltage of the first secondary winding are not equal. I will try. Further, when the output voltage of the DC source is applied to the second secondary winding, the output voltage of the DC source tends to be equal to the winding voltage of the second secondary winding. Therefore, since the winding voltage of the first secondary winding and the winding voltage of the second secondary winding are going to be equal, the same effect as described above can be achieved.

  (9) According to the present invention, in the cell balance circuit of (8), fourth switching means for controlling whether or not to apply the output voltage of the DC source to the second secondary winding (for example, FIG. 14). The first switching means and the third switching means operate in synchronism, and the second switching means and the fourth switching means synchronize with each other. A cell balance circuit characterized by operation is proposed.

  According to the present invention, in the cell balance circuit of (8), the fourth switching means for controlling whether or not the output voltage of the DC source is applied to the second secondary winding is provided, and the first switching means And the third switching means are operated in synchronization, and the second switching means and the fourth switching means are operated in synchronization. According to this, an effect similar to the effect mentioned above can be produced.

  (10) In the cell balance circuit according to (9), the first switching means and the third switching means, and the second switching means and the fourth switching means operate asynchronously. A cell balance circuit characterized by the above is proposed.

  Here, as described above, whether or not the output voltage of the DC source is applied to the first secondary winding is controlled by the third switching means, and the output voltage of the DC source is controlled by the fourth switching means. Is applied to the second secondary winding. For this reason, the voltage of the wiring between the first secondary winding and the DC source and the voltage of the wiring between the second secondary winding and the DC source are DC. Therefore, if the first switching means and the third switching means are synchronously controlled, and the second switching means and the fourth switching means are synchronously controlled, the first switching means and the third switching means The means, the second switching means and the fourth switching means may be asynchronous control.

  Therefore, according to the present invention, in the cell balance circuit of (9), the first switching means and the third switching means, and the second switching means and the fourth switching means are operated asynchronously. did. Therefore, the wiring delay in the wiring for transmitting the control signal to the first switching means and the third switching means, and the wiring delay in the wiring for transmitting the control signal to the second switching means and the fourth switching means, Since it is not necessary to consider equalization, these wirings can be lengthened and the switching means can be easily controlled, so that the design of the cell balance circuit can be further facilitated.

  (11) In the cell balance circuit according to (9) or (10), the third switching means includes a high potential side terminal of the DC source, one end of the first secondary winding, , A fifth procedure for connecting the low potential side terminal of the DC source and the other end of the first secondary winding, the high potential side terminal of the DC source, and the first A sixth step of connecting the other end of the secondary winding to the low potential side terminal of the DC source and one end of the first secondary winding. The switching means connects the high potential side terminal of the DC source and one end of the second secondary winding, and also connects the low potential side terminal of the DC source and the second secondary winding. A seventh step of connecting the other end of the DC source, a high potential side terminal of the DC source, and the other end of the second secondary winding. Moni, proposes a low-potential-side terminal of the DC source, and an eighth procedure for connecting one end of the second secondary winding, and the cell balance circuit and performs.

  According to the present invention, in the cell balance circuit of (9) or (10), the fifth procedure and the sixth procedure are performed by the third switching means, and the seventh procedure and the eighth procedure are performed by the fourth switching means. It was decided. In the fifth procedure, the high potential side terminal of the DC source and one end of the first secondary winding are connected, and the low potential side terminal of the DC source and the other end of the first secondary winding are connected to each other. In the sixth procedure, the high potential side terminal of the DC source and the other end of the first secondary winding are connected, the low potential side terminal of the DC source, and the first secondary side It was decided to connect one end of the winding. In the seventh procedure, the high potential side terminal of the direct current source and one end of the second secondary winding are connected, and the low potential side terminal of the direct current source and the other secondary winding are connected. In the eighth procedure, the high-potential side terminal of the DC source and the other end of the second secondary winding are connected, the low-potential side terminal of the DC source, and the second One end of the secondary winding is connected.

  Here, when the polarity of the voltage at one end with respect to the other end of the first primary winding is reversed, the polarity of the voltage at one end with respect to the other end of the first secondary winding is also reversed. Therefore, according to the polarity reversal of the winding voltage of the first primary winding, the one connected to the high potential side terminal of the DC source among the one end and the other end of the first secondary winding is the third one. By switching by the switching means, it is possible to continue to connect the higher potential side of the first secondary winding to the higher potential side terminal of the DC source. For this reason, even when an alternating voltage is applied to the first primary winding, the voltage of the wiring between the first secondary winding and the direct current source becomes a direct current. Therefore, if it is alternating current, it is affected by the inductor component of the wiring, but since it is direct current, the influence of the inductor component of the wiring can be suppressed, and the wiring between the first secondary winding and the direct current source can be reduced. Can be long. Since the voltage of the wiring between the second secondary winding and the DC source is also DC like the voltage of the wiring between the first secondary winding and the DC source, the second secondary winding The wiring between the winding and the DC source can also be lengthened. As described above, the design of the cell balance circuit can be facilitated.

  Further, the voltage of the wiring between the first secondary winding and the DC source and the voltage of the wiring between the second secondary winding and the DC source are both DC as described above. . Therefore, the third switching means is controlled in synchronization with the polarity reversal of the winding voltage of the first primary winding, and the second switching means is synchronized with the polarity reversal of the winding voltage of the second primary winding. As long as the four switching means are controlled, the third switching means and the fourth switching means may be asynchronous control. Therefore, the arrangement and control of the third switching means and the fourth switching means can be facilitated, and the design of the cell balance circuit can be further facilitated.

  (12) In the cell balance circuit according to any one of (7) to (11), the present invention is characterized in that the first transformer and the second transformer each include iron cores separated from each other. A cell balance circuit is proposed.

  Here, let us consider a case where the first secondary battery and the second secondary battery are not arranged close to each other. In this case, if the iron core of the first transformer and the iron core of the second transformer are integrally formed, it becomes difficult to design the cell balance circuit.

  Therefore, according to the present invention, in any of the cell balance circuits of (7) to (11), each of the first transformer and the second transformer includes an iron core separated from each other. For this reason, when the first secondary battery and the second secondary battery are not arranged close to each other, the first transformer is provided in the vicinity of the first secondary battery, and the second secondary battery A second transformer can be provided in the vicinity. Therefore, the design of the cell balance circuit can be facilitated.

  According to the invention, in any of the cell balance circuits of (7) to (11), as described above, the first transformer and the second transformer each include an iron core. For this reason, since the magnetic flux which generate | occur | produces in a 1st transformer and a 2nd transformer can be stabilized compared with the case where an iron core is not provided, a cell balance can be stabilized more accurately.

  (13) In the cell balance circuit according to any one of (7) to (12), the number of turns of the first secondary winding and the second secondary winding is the first primary A cell balance circuit is proposed in which the number of turns is larger than that of the winding and the second primary winding.

  According to the present invention, in the cell balance circuit according to any one of (7) to (12), the number of turns of the first secondary winding and the second secondary winding is the first primary winding and the second secondary winding. The number of turns of the primary winding No. 2 is larger than that of the primary winding. Therefore, the current flowing between the first secondary winding and the direct current source can be made smaller than the current flowing through the first primary winding, and the second secondary winding and the direct current source Can be made smaller than the current flowing in the second primary winding. Therefore, loss in the first secondary winding and the second secondary winding can be reduced.

(14) In the cell balance circuit according to any one of (7) to (13), the present invention is characterized in that the first switching means forms a non-resonant circuit (for example, see FIGS. 12 to 16 ). A cell balance circuit is proposed.

  According to this invention, in the cell balance circuit of any one of (7) to (13), the first switching means forms a non-resonant converter. For this reason, the effect similar to the effect mentioned above can be show | played by switching appropriately the switch element provided in a non-resonance type | mold converter.

  According to the present invention, the first secondary battery and the second secondary battery can be realized while realizing cost reduction and downsizing, and suppression of deterioration of the first secondary battery and the second secondary battery. The charging voltage can be made uniform during charging / discharging of the battery.

1 is a circuit diagram of a cell balance circuit according to a first embodiment of the present invention. 1 is an equivalent circuit diagram of a cell balance circuit according to a first embodiment of the present invention. 1 is an equivalent circuit diagram of a cell balance circuit according to a first embodiment of the present invention. 1 is an equivalent circuit diagram of a cell balance circuit according to a first embodiment of the present invention. It is a circuit diagram of the cell balance circuit which concerns on 2nd Embodiment of this invention. It is a circuit diagram of a cell balance apparatus provided with the cell balance circuit which concerns on 3rd Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 4th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 5th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 6th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 7th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 8th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 9th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 10th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 11th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 12th Embodiment of this invention. It is a circuit diagram of the cell balance circuit which concerns on 13th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the constituent elements in the following embodiments can be appropriately replaced with existing constituent elements, and various variations including combinations with other existing constituent elements are possible. Accordingly, the description of the following embodiments does not limit the contents of the invention described in the claims.

<First Embodiment>
[Configuration of Cell Balance Circuit AA]
FIG. 1 is a circuit diagram of a cell balance circuit AA according to the first embodiment of the present invention. The cell balance circuit AA equalizes the charging voltages of the secondary batteries BT1 and BT2. The secondary batteries BT1 and BT2 are connected to a charging circuit (not shown), are charged by the charging circuit, and are connected to a load (not shown), and supply power to the load in response to a request from the load. Is discharged.

  The cell balance circuit AA includes a transformer T, a switch SW1 provided in a pair with the secondary battery BT1, and a switch SW2 provided in a pair with the secondary battery BT2. The switches SW1 and SW2 are composed of, for example, MOSFET, IGBT, or BJT. The transformer T includes a first winding Wa provided in a pair with the secondary battery BT1, and a second winding Wb provided in a pair with the secondary battery BT2. The first winding Wa and the second winding Wb are wound around the same iron core, and the number of turns of the first winding Wa is equal to the number of turns of the second winding Wb.

  One end of the first winding Wa is connected to one end of the secondary battery BT1, and the other end of the first winding Wa is connected to the other end of the secondary battery BT1 via the switch SW1. One end of the secondary battery BT2 is connected to one end of the second winding Wb, and the other end of the secondary battery BT2 is connected to the other end of the second winding Wb via the switch SW2.

[Operation of Cell Balance Circuit AA]
If the charge voltage of the secondary battery BT1 and the charge voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, the cell balance circuit AA having the above-described configuration will resemble the secondary battery BT1. , Current is passed through BT2, and the respective charging voltages of the secondary batteries BT1, BT2 are made uniform. A specific operation of the cell balance circuit AA will be described in detail below.

  The cell balance circuit AA controls the switches SW1 and SW2 synchronously by a control unit (not shown) when the secondary batteries BT1 and BT2 are charged and discharged. When the switches SW1 and SW2 are turned on, the charging voltage of the secondary battery BT1 is applied to the first winding Wa, and the charging voltage of the secondary battery BT2 is applied to the second winding Wb. Become.

  When the charging voltage of the secondary battery BT1 is applied to the first winding Wa, a magnetic flux is generated in the first winding Wa, and this magnetic flux passes through the second winding Wb. In Wb, an electromotive force similar to that shown in the above equation (1) is generated.

  Here, the magnetic flux generated in the first winding Wa changes according to the voltage applied to the first winding Wa. For this reason, the electromotive force generated in the second winding Wb changes according to the charging voltage of the secondary battery BT1.

  In the second winding Wb as well, the magnetic flux is generated when the charging voltage of the secondary battery BT2 is applied, and the magnetic flux penetrates the first winding Wa. In the first winding Wa, an electromotive force similar to that shown in the above formula (1) is generated. And the electromotive force which generate | occur | produces in the 1st coil | winding Wa will change according to the charging voltage of secondary battery BT2.

  Here, when the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are equal, no current flows through the first winding Wa as in the above-described formula (2), and the above-mentioned As in the formula (3), no current flows through the second winding Wb, so no current flows through the secondary battery BT1 and the secondary battery BT2.

  On the other hand, when the charging voltage of the secondary battery BT1 is lower than the charging voltage of the secondary battery BT2, the above equation (2) is applied until the charging voltage of the secondary battery BT1 becomes equal to the charging voltage of the secondary battery BT2. Current flows from the first winding Wa to the secondary battery BT1, and the secondary battery BT1 is charged. Further, until the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 become equal, the current determined by the above equation (3) flows from the secondary battery BT2 to the second winding Wb, and the secondary battery BT1 is charged. Battery BT2 is discharged.

  When the charging voltage of the secondary battery BT1 is higher than the charging voltage of the secondary battery BT2, the above equation (2) is satisfied until the charging voltage of the secondary battery BT1 becomes equal to the charging voltage of the secondary battery BT2. Current flows from the secondary battery BT1 to the first winding Wa, and the secondary battery BT1 is discharged. Further, until the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 become equal, the current determined by the above equation (3) flows from the second winding Wb to the secondary battery BT2, and the secondary battery BT2 Battery BT2 is charged.

  As described above, when the secondary batteries BT1 and BT2 are charged and discharged, the charging voltage of the secondary battery BT1 is equal to the charging voltage of the secondary battery BT2.

  According to the above cell balance circuit AA, the following effects can be obtained.

  The cell balance circuit AA equalizes the respective charging voltages of the secondary batteries BT1 and BT2 without using the diode required by the circuit shown in the above-mentioned Patent Document 1. Further, the respective charging voltages of the secondary batteries BT1 and BT2 are made uniform when the secondary batteries BT1 and BT2 are charged and discharged. Therefore, the charging voltages of the secondary batteries BT1 and BT2 can be accurately equalized not only when the secondary batteries BT1 and BT2 are charged but also discharged, and the cell balance can be stabilized.

  Further, the cell balance circuit AA can equalize the charging voltages of the secondary batteries BT1 and BT2 without using the charging voltages of the secondary batteries BT1 and BT2. For this reason, it is not necessary to monitor the charging voltages of the secondary batteries BT1 and BT2, so that the cost and size of the cell balance circuit AA can be reduced.

  The cell balance circuit AA can equalize the respective charging voltages of the secondary batteries BT1 and BT2 during charging and discharging of the secondary batteries BT1 and BT2, and therefore temporarily reaches the deterioration region. Can be prevented and deterioration of the secondary batteries BT1 and BT2 can be suppressed.

  Moreover, when one resistor is connected in parallel to each of the plurality of secondary batteries as described above, the current that can be passed through these secondary batteries is limited by these resistors. On the other hand, the cell balance circuit AA is provided with a transformer T but not a resistor. Since the resistance values of the first winding Wa and the second winding Wb provided in the transformer T are significantly smaller than the resistance value of the resistance, the current limited by the transformer T is limited by the resistance. Significantly smaller than current. For this reason, the electric current which can be sent through secondary battery BT1 and BT2 can be enlarged compared with the case where one resistance is connected in parallel with respect to each of secondary batteries BT1 and BT2.

  The first winding Wa and the second winding Wb are wound around the same iron core. Therefore, when the first winding Wa and the second winding Wb are not wound around the iron core, that is, when the first winding Wa and the second winding Wb are empty, Since the magnetic flux generated in the first winding Wa and the second winding Wb can be stabilized, the cell balance can be stabilized with higher accuracy.

Second Embodiment
[Configuration of Cell Balance Circuit BB]
FIG. 5 is a circuit diagram of a cell balance circuit BB according to the second embodiment of the present invention. The cell balance circuit BB is a modification of the cell balance circuit AA according to the first embodiment of the present invention shown in FIG. The relationship between the cell balance circuit AA and the cell balance circuit BB will be described with reference to FIGS.

  The cell balance circuit AA of FIG. 1 can also be expressed as shown in FIG.

  FIG. 3 is a circuit diagram of the cell balance circuit AB. The cell balance circuit AB is an equivalent circuit of the cell balance circuit AA shown in FIG. The cell balance circuit AB is different from the cell balance circuit AA in that secondary batteries BT1 and BT2 are connected in series. In the cell balance circuit AB, the same components as those of the cell balance circuit AA are denoted by the same reference numerals, and the description thereof is omitted.

  The cell balance circuit AB shown in FIG. 3 can also be expressed as shown in FIG.

  The cell balance circuit AB shown in FIG. 4 can achieve the same effect as the cell balance circuit AA by controlling the switches SW1 and SW2. However, since the secondary batteries BT1 and BT2 output direct-current power, in the cell balance circuit AA and the cell balance circuit AB shown in FIGS. The transformer T is saturated. The cell balance circuit BB according to the second embodiment of the present invention shown in FIG. 5 can prevent the transformer T from being saturated.

  The cell balance circuit BB differs from the cell balance circuit AB shown in FIG. 4 in that it includes switches Sa, Sb, Sc, and Sd instead of the switches SW1 and SW2. The switches Sa, Sb, Sc, and Sd are configured by, for example, MOSFET, IGBT, or BJT. In the cell balance circuit BB, the same components as those in the cell balance circuit AB shown in FIG.

  The other end of the secondary battery BT1 and one end of the secondary battery BT2 are connected to the other end of the first winding Wa and one end of the second winding Wb. One end of the first winding Wa is connected to one end of the secondary battery BT1 through the switch Sa, and the other end of the secondary battery BT2 is connected through the switch Sb. One end of the secondary battery BT1 is connected to the other end of the second winding Wb via the switch Sc, and the other end of the secondary battery BT2 is connected via the switch Sd.

[Operation of Cell Balance Circuit BB]
When the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, the cell balance circuit BB supplies current to the secondary batteries BT1 and BT2. The charge voltages of the secondary batteries BT1 and BT2 are made uniform. A specific operation of the cell balance circuit BB will be described in detail below.

  When the secondary batteries BT1 and BT2 are charged and discharged, the cell balance circuit BB turns on the switches Sa and Sd, and the switches Sb and Sc alternately at a duty ratio of 50% by a control unit (not shown). To.

  When the switch Sa and the switch Sd are turned on and the switch Sb and the switch Sc are turned off, the charging voltage of the secondary battery BT1 is applied to the first winding Wa, and the second winding Wb The charging voltage of the secondary battery BT2 is applied to the secondary battery BT2. On the other hand, when the switch Sa and the switch Sd are turned off and the switch Sb and the switch Sc are turned on, the charging voltage of the secondary battery BT2 is applied to the first winding Wa, and the second winding The charging voltage of the secondary battery BT1 is applied to the line Wb. However, when the switch Sa and the switch Sd are turned on and the switch Sb and the switch Sc are turned off, and when the switch Sa and the switch Sd are turned off and the switch Sb and the switch Sc are turned on Then, the polarity of the voltage at one end with respect to the other end of the first winding Wa is reversed, and the polarity of the voltage at one end with respect to the other end of the second winding Wb is also reversed.

  According to the above cell balance circuit BB, in addition to the above-described effects that can be achieved by the cell balance circuit AA according to the first embodiment of the present invention shown in FIG. 1, the following effects can be achieved.

  The switches Sa and Sd and the switches Sb and Sc are alternately turned on at a duty ratio of 50%. For this reason, every time the switches Sa, Sb, Sc, Sd are turned on and off, the polarity of the voltage at one end with respect to the other end of the first winding Wa is reversed, and the other end of the second winding Wb The polarity of the voltage at one end with respect to is also reversed. According to this, it is possible to prevent the transformer T from being saturated.

  Each of the switches Sa, Sb, Sc, Sd has a duty ratio of 50%. For this reason, the cell balance circuit AA can equalize each charging voltage of the secondary batteries BT1 and BT2 more accurately.

<Third Embodiment>
[Configuration of Cell Balance Device 1]
FIG. 6 is a circuit diagram of the cell balance device 1 including the cell balance circuits CC and DD according to the third embodiment of the present invention. The cell balance device 1 equalizes the charging voltages of the secondary batteries BT1 to BT3 connected in series. The secondary batteries BT1 to BT3 are connected to a charging circuit (not shown), are charged by the charging circuit, and are connected to a load (not shown), and supply power to the load in response to a request from the load. Is discharged.

  The cell balance device 1 includes a cell balance circuit CC that equalizes the charging voltages of the secondary batteries BT1 and BT2, and a cell balance circuit DD that equalizes the charging voltages of the secondary batteries BT2 and BT3. . Each of the cell balance circuits CC and DD is different from the cell balance circuit BB according to the second embodiment of the present invention shown in FIG. 5 in that the cell balance circuits CC and DD are provided integrally with the secondary batteries BT1 and BT2. In the cell balance circuits CC and DD, the same components as those of the cell balance circuit BB are denoted by the same reference numerals, and the description thereof is omitted.

[Operation of Cell Balance Device 1]
The cell balance device 1 having the above configuration operates the cell balance circuits CC and DD similarly to the cell balance circuit BB when the secondary batteries BT1 to BT3 are charged and discharged, thereby operating the secondary batteries BT1 to BT3. Each charging voltage is made uniform.

  According to each of the above cell balance circuits CC and DD, in addition to the above-described effects that the cell balance circuit BB according to the second embodiment of the present invention shown in FIG. Can do.

  Since the cell balance circuit CC and the secondary battery BT1 are provided integrally, and the cell balance circuit DD and the secondary battery BT2 are provided integrally, the size can be reduced as compared with the case where they are provided separately. it can.

  Moreover, according to the above cell balance apparatus 1, there can exist the following effects.

  When the secondary batteries BT1 to BT3 are charged and discharged, the cell balance circuit CC equalizes the charge voltages of the secondary batteries BT1 and BT2, and the cell balance circuit DD sets the charge voltages of the secondary batteries BT2 and BT3. Homogenize. For this reason, the cell balance device 1 can equalize the respective charging voltages of the secondary batteries BT1 to BT3 not only when charging the secondary batteries BT1 to BT3 but also when discharging, thereby stabilizing the cell balance. Can do.

  Further, the switching of the switches Sa, Sb, Sc, and Sd can be made asynchronous between the cell balance circuit CC and the cell balance circuit DD. For this reason, since it is not necessary to synchronize switching of these switches Sa, Sb, Sc, and Sd between the cell balance circuit CC and the cell balance circuit DD, switching control can be facilitated, and the cell balance device 1 design can be facilitated.

<Fourth embodiment>
[Configuration of Cell Balance Circuit EE]
FIG. 7 is a circuit diagram of a cell balance circuit EE according to the fourth embodiment of the present invention. The cell balance circuit EE differs from the cell balance circuit BB according to the second embodiment of the present invention shown in FIG. 5 in that the switch elements Q1 to Q8 are configured by N-channel MOSFETs instead of the switches Sa, Sb, Sc and Sd. Is different. In the cell balance circuit EE, the same constituent elements as those of the cell balance circuit BB are denoted by the same reference numerals, and the description thereof is omitted.

  The switch elements Q1 to Q4 are provided in pairs with the secondary battery BT1 to form a so-called full bridge circuit. Specifically, one end of the secondary battery BT1 is connected to the drain of the switch element Q1 and the drain of the switch element Q3. The source of the switch element Q1 is connected to the drain of the switch element Q2 and one end of the first winding Wa. The source of the switch element Q3 is connected to the drain of the switch element Q4 and the other end of the first winding Wa. The other end of the secondary battery BT1 is connected to the source of the switch element Q2 and the source of the switch element Q4.

  The switch elements Q5 to Q8 are also provided in pairs with the secondary battery BT2 similarly to the switch elements Q1 to Q4 described above, and form a so-called full bridge circuit.

[Operation of cell balance circuit EE]
If the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, the cell balance circuit EE supplies current to the secondary batteries BT1 and BT2. The charge voltages of the secondary batteries BT1 and BT2 are made uniform. A specific operation of the cell balance circuit EE will be described in detail below.

  When the secondary batteries BT1 and BT2 are charged and discharged, the cell balance circuit EE applies duty to the switch elements Q1, Q4, Q5, and Q8 and the switch elements Q2, Q3, Q6, and Q7 by a control unit (not shown). It turns on alternately at a ratio of 50%. According to this, the charging voltage of the secondary battery BT1 is applied to the first winding Wa, and the charging voltage of the secondary battery BT2 is applied to the second winding Wb. Similarly to the cell balance circuit BB, the polarity of the voltage at one end with respect to the other end of the first winding Wa is reversed according to the switching of the switching elements Q1 to Q8, and the second winding Wb. The polarity of the voltage at one end with respect to the other end is also reversed.

  According to the above cell balance circuit EE, it is possible to achieve the same effects as those described above that can be achieved by the cell balance circuit BB according to the second embodiment of the present invention shown in FIG.

<Fifth Embodiment>
[Configuration of Cell Balance Circuit FF]
FIG. 8 is a circuit diagram of a cell balance circuit FF according to the fifth embodiment of the present invention. The cell balance circuit FF is different from the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 in that capacitors C1 to C4 are provided instead of the switch elements Q1, Q2, Q5, and Q6. In the cell balance circuit FF, the same components as those of the cell balance circuit EE are denoted by the same reference numerals, and the description thereof is omitted.

  Switch elements Q3, Q4 and capacitors C1, C2 are provided in pairs with secondary battery BT1 to form a so-called half-bridge circuit. Specifically, one end of the secondary battery BT1 is connected to one electrode of the capacitor C1, and one electrode of the capacitor C2 and one end of the first winding Wa are connected to the other electrode of the capacitor C1. , Are connected. The other electrode of the secondary battery BT1 is connected to the other electrode of the capacitor C2.

  The switch elements Q7, Q8 and the capacitors C3, C4 are also provided in pairs with the secondary battery BT2, similarly to the above-described switch elements Q3, Q4 and capacitors C1, C2, and form a so-called half-bridge circuit.

[Operation of cell balance circuit FF]
Similarly to the cell balance circuit EE, the cell balance circuit FF is configured so that if the charge voltage of the secondary battery BT1 and the charge voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, these 2 By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform.

  According to the cell balance circuit FF described above, the same effects as those described above that can be achieved by the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 can be achieved.

<Sixth Embodiment>
[Configuration of Cell Balance Circuit GG]
FIG. 9 is a circuit diagram of a cell balance circuit GG according to the sixth embodiment of the present invention. The cell balance circuit GG is different from the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 in that diodes D1 to D4 are provided instead of the switch elements Q2, Q3, Q6, and Q7. In the cell balance circuit GG, the same components as those of the cell balance circuit EE are denoted by the same reference numerals and description thereof is omitted.

  Switch elements Q1, Q4 and diodes D1, D2 are provided in a pair with secondary battery BT1, and form a so-called forward circuit. Specifically, one end of the secondary battery BT1 is connected to the cathode of the diode D1, and the drain of the switch element Q4 and the other end of the first winding Wa are connected to the anode of the diode D1. The The source of the switching element Q1 and one end of the first winding Wa are connected to the cathode of the diode D2, and the other end of the secondary battery BT1 is connected to the anode of the diode D2.

  The switch elements Q5 and Q8 and the diodes D3 and D4 are also provided in pairs with the secondary battery BT2 in the same manner as the switch elements Q1 and Q4 and the diodes D1 and D2, and form a so-called forward circuit.

[Operation of Cell Balance Circuit GG]
Similarly to the cell balance circuit EE, the cell balance circuit GG is configured so that if the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, these 2 By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform.

  According to the above cell balance circuit GG, the same effects as those described above that can be achieved by the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 can be achieved.

<Seventh embodiment>
[Configuration of Cell Balance Circuit HH]
FIG. 10 is a circuit diagram of a cell balance circuit HH according to the seventh embodiment of the present invention. The cell balance circuit HH is different from the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 in that the switch elements Q1, Q3, Q5, and Q7 are not provided, and in the first winding Wa. And the point of using the middle point of the second winding Wb. In the cell balance circuit HH, the same components as those of the cell balance circuit EE are denoted by the same reference numerals, and the description thereof is omitted.

  The switch elements Q2, Q4 are provided in a pair with the secondary battery BT1, and form a so-called push-pull type circuit. Specifically, one end of the first winding Wa is connected to the drain of the switching element Q2, and the other end of the first winding Wa is connected to the drain of the switching element Q4. The other end of the secondary battery BT1 is connected to the source of the switch element Q2 and the source of the switch element Q4. A midpoint of the first winding Wa is connected to one end of the secondary battery BT1.

  The switch elements Q6 and Q8 are also provided in pairs with the secondary battery BT2 similarly to the switch elements Q2 and Q4 described above, and form a so-called push-pull type circuit.

[Operation of cell balance circuit HH]
Similarly to the cell balance circuit EE, the cell balance circuit HH is configured so that if the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, these 2 By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform.

  According to the cell balance circuit HH described above, the same effects as those described above that can be achieved by the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 can be achieved.

<Eighth Embodiment>
[Configuration of Cell Balance Circuit JJ]
FIG. 11 is a circuit diagram of a cell balance circuit JJ according to the eighth embodiment of the present invention. The cell balance circuit JJ differs from the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 in that capacitors C5 and C6 are provided instead of the switch elements Q1, Q2, Q5, and Q6. In the cell balance circuit JJ, the same components as those of the cell balance circuit EE are denoted by the same reference numerals and description thereof is omitted.

  Switch elements Q3, Q4 and capacitor C5 are provided in a pair with secondary battery BT1, and form a so-called active clamp type forward circuit. Specifically, one end of the secondary battery BT1 and one end of the first winding Wa are connected to the drain of the switching element Q3 via the capacitor C5. The source of the switch element Q3 is connected to the drain of the switch element Q4 and the other end of the first winding Wa.

  Switch elements Q7 and Q8 and capacitor C6 are also provided in pairs with secondary battery BT2 in the same manner as switch elements Q3 and Q4 and capacitor C5 described above to form a so-called active clamp type forward circuit.

[Operation of cell balance circuit JJ]
Similar to the cell balance circuit EE, the cell balance circuit JJ can be configured so that the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are different when charging and discharging the secondary batteries BT1 and BT2, respectively. By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform.

  According to the above cell balance circuit JJ, the same effects as those described above that can be achieved by the cell balance circuit EE according to the fourth embodiment of the present invention shown in FIG. 7 can be achieved.

<Ninth Embodiment>
[Configuration of Cell Balance Circuit KK]
FIG. 12 is a circuit diagram of the cell balance circuit KK according to the ninth embodiment of the present invention. The cell balance circuit KK differs from the cell balance circuit AB shown in FIG. 3 in that it includes transformers T1 and T2 instead of the transformer T. In the cell balance circuit KK, the same components as those of the cell balance circuit AB are denoted by the same reference numerals, and the description thereof is omitted.

  The transformer T1 includes a primary winding W11 and a secondary winding W12 provided in a pair with the secondary battery BT1. The transformer T2 includes a primary winding W21 and a secondary winding W22 provided in a pair with the secondary battery BT2.

  The number of turns of the primary winding W11 is equal to the number of turns of the primary winding W21. Further, the number of turns of the secondary winding W12 is equal to the number of turns of the secondary winding W22. Further, the number of turns of the secondary windings W12 and W22 is larger than the number of turns of the primary windings W11 and W21.

  Each of the transformers T1 and T2 includes an iron core, and the iron core of the transformer T1 and the iron core of the transformer T2 are separated.

  One end of the secondary battery BT1 is connected to one end of the primary winding W11, and the other end of the secondary battery BT1 is connected to the other end of the primary winding W11 via the switch SW1. One end of the secondary battery BT2 is connected to one end of the primary winding W21, and the other end of the secondary battery BT2 is connected to the other end of the primary winding W21 via the switch SW2.

  Secondary winding W12 and secondary winding W22 are connected in parallel.

[Operation of cell balance circuit KK]
Similarly to the cell balance circuit AB, the cell balance circuit KK may be configured so that the charge voltage of the secondary battery BT1 and the charge voltage of the secondary battery BT2 are different when charging and discharging the secondary batteries BT1 and BT2. By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform. A specific operation of the cell balance circuit KK will be described below.

  The cell balance circuit KK synchronously controls the switches SW1 and SW2 by a control unit (not shown) when the secondary batteries BT1 and BT2 are charged and discharged. When the switches SW1 and SW2 are turned on, the charging voltage of the secondary battery BT1 is applied to the primary winding W11, and the charging voltage of the secondary battery BT2 is applied to the primary winding W21.

When the charging voltage of the secondary battery BT1 is applied to the primary winding W11, a magnetic flux is generated in the primary winding W11, and this magnetic flux passes through the secondary winding W12. An electromotive force similar to that shown in the above-described equation (1) is generated. In the relationship between the primary winding W11 and the secondary winding W12 described above, Φ _B in the above formula (1) indicates a magnetic flux generated in the primary winding W11 and penetrating the secondary winding W12. , N represents the number of turns of the secondary winding W12, and ε represents the electromotive force generated in the secondary winding W12.

  Here, the magnetic flux generated in the primary winding W11 changes according to the voltage applied to the primary winding W11. For this reason, the electromotive force generated in the secondary winding W12 changes according to the charging voltage of the secondary battery BT1.

  Also in the primary winding W21, similarly to the above-described primary winding W11, when the charging voltage of the secondary battery BT2 is applied, a magnetic flux is generated, and this magnetic flux penetrates the secondary winding W22. In the winding W22, an electromotive force similar to that shown in the above equation (1) is generated. The electromotive force generated in the secondary winding W22 changes according to the charging voltage of the secondary battery BT2.

  Here, as described above, the number of turns of the primary winding W11 and the number of turns of the primary winding W21 are equal, and the number of turns of the secondary winding W12 and the number of turns of the secondary winding W22 are equal. For this reason, the ratio of the winding voltage of the primary winding W11 and the winding voltage of the secondary winding W12 is the winding voltage of the primary winding W21 and the winding voltage of the secondary winding W22. Is equal to the ratio of. Therefore, the ratio of the charging voltage of the secondary battery BT1 and the winding voltage of the secondary winding W12 is equal to the ratio of the charging voltage of the secondary battery BT2 and the winding voltage of the secondary winding W22. Become. Therefore, the ratio of the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 is equal to the ratio of the winding voltage of the secondary winding W12 and the winding voltage of the secondary winding W22. Become.

  According to the above, when the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are equal, the winding voltage of the secondary winding W12 and the winding voltage of the secondary winding W22 are: Will be equal. On the other hand, when the charging voltage of the secondary battery BT1 is lower than the charging voltage of the secondary battery BT2, the winding voltage of the secondary winding W12 is lower than the winding voltage of the secondary winding W22. When the charging voltage of the secondary battery BT1 is higher than the charging voltage of the secondary battery BT2, the winding voltage of the secondary winding W12 is higher than the winding voltage of the secondary winding W22.

  Here, the secondary winding W12 and the secondary winding W22 are connected in parallel as described above. Therefore, current flows between the secondary windings W12 and W22 until the winding voltage of the secondary winding W12 becomes equal to the winding voltage of the secondary winding W22. The charging voltage and the charging voltage of the secondary battery BT2 are about to be equal.

  For this reason, when the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 are equal, the winding voltage of the secondary winding W12 and the winding voltage of the secondary winding W22 are as described above. Therefore, no current flows between the secondary winding W12 and the secondary winding W22. Therefore, no current flows through the secondary battery BT1 and the secondary battery BT2.

  On the other hand, when the charging voltage of the secondary battery BT1 is lower than the charging voltage of the secondary battery BT2, the winding voltage of the secondary winding W12 is lower than the winding voltage of the secondary winding W22 as described above. Until the winding voltage of the secondary winding W12 is equal to the winding voltage of the secondary winding W22, that is, until the charging voltage of the secondary battery BT1 is equal to the charging voltage of the secondary battery BT2. A current flows from the secondary winding W22 to the secondary winding W12. Therefore, current flows from the primary winding W11 to the secondary battery BT1 until the charge voltage of the secondary battery BT1 becomes equal to the charge voltage of the secondary battery BT2, and the secondary battery BT1 is charged. Further, a current flows from the secondary battery BT2 to the primary winding W21 until the charging voltage of the secondary battery BT1 becomes equal to the charging voltage of the secondary battery BT2, and the secondary battery BT2 is discharged.

  Further, when the charging voltage of the secondary battery BT1 is higher than the charging voltage of the secondary battery BT2, the winding voltage of the secondary winding W12 becomes higher than the winding voltage of the secondary winding W22 as described above. Until the winding voltage of the secondary winding W12 is equal to the winding voltage of the secondary winding W22, that is, until the charging voltage of the secondary battery BT1 is equal to the charging voltage of the secondary battery BT2. A current flows from the secondary winding W12 to the secondary winding W22. Therefore, current flows from the secondary battery BT1 to the primary winding W11 until the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 become equal, and the secondary battery BT1 is discharged. Further, current flows from the primary winding W21 to the secondary battery BT2 until the charge voltage of the secondary battery BT1 becomes equal to the charge voltage of the secondary battery BT2, and the secondary battery BT2 is charged.

  As described above, when the secondary batteries BT1 and BT2 are charged and discharged, the charging voltage of the secondary battery BT1 is equal to the charging voltage of the secondary battery BT2.

  The current flowing between the secondary windings W12 and W22 is determined according to the number of turns of the primary windings W11 and W21 and the number of turns of the secondary windings W12 and W22. Specifically, the turns ratio of the number of turns of each of the primary windings W11 and W21 and the number of turns of each of the secondary windings W12 and W22 is “1: n” (n satisfies n> 1). (Any number) If the current flowing through each of the primary windings W11 and W21 is I1, and the current flowing through each of the secondary windings W12 and W22 is I2, the relationship of the following equation (4) is established.

  According to the above cell balance circuit KK, the following effects can be obtained.

  The cell balance circuit KK equalizes the respective charging voltages of the secondary batteries BT1 and BT2 without using the diodes required by the circuit shown in Patent Document 1 described above. Further, the respective charging voltages of the secondary batteries BT1 and BT2 are made uniform when the secondary batteries BT1 and BT2 are charged and discharged. Therefore, the charging voltages of the secondary batteries BT1 and BT2 can be accurately equalized not only when the secondary batteries BT1 and BT2 are charged but also discharged, and the cell balance can be stabilized.

  Further, the cell balance circuit KK can equalize the charging voltages of the secondary batteries BT1 and BT2 without using the charging voltages of the secondary batteries BT1 and BT2. For this reason, it is not necessary to monitor the charging voltages of the secondary batteries BT1 and BT2, so the cost and size of the cell balance circuit KK can be reduced.

  In addition, the cell balance circuit KK can equalize the respective charging voltages of the secondary batteries BT1 and BT2 during charging and discharging of the secondary batteries BT1 and BT2, and thus temporarily reach the deterioration region. Can be prevented and deterioration of the secondary batteries BT1 and BT2 can be suppressed.

  Moreover, when one resistor is connected in parallel to each of the plurality of secondary batteries as described above, the current that can be passed through these secondary batteries is limited by these resistors. In contrast, the cell balance circuit KK is provided with transformers T1 and T2, but is not provided with a resistor. Since the resistance values of the primary windings W11 and W21 and the secondary windings W12 and W22 provided in the transformers T1 and T2 are significantly smaller than the resistance values of the resistors, the current limited by the transformers T1 and T2 is This is much smaller than the current limited by the resistance. For this reason, the electric current which can be sent through secondary battery BT1 and BT2 can be enlarged compared with the case where one resistance is connected in parallel with respect to each of secondary batteries BT1 and BT2.

  In the cell balance circuit KK, the transformers T1 and T2 include iron cores. For this reason, compared with the case where the iron core is not provided, the magnetic flux generated in each of the transformers T1 and T2 can be stabilized, so that the cell balance can be stabilized with higher accuracy.

  In the cell balance circuit KK, the iron core of the transformer T1 and the iron core of the transformer T2 are separated. For this reason, when the secondary batteries BT1 and BT2 are not arranged close to each other, the transformer T1 can be provided in the vicinity of the secondary battery BT1, and the transformer T2 can be provided in the vicinity of the secondary battery BT2. Therefore, the design of the cell balance circuit KK can be facilitated.

  In the cell balance circuit KK, the number of turns of each of the secondary windings W12 and W22 is larger than the number of turns of each of the primary windings W11 and W21. For this reason, as shown in the above equation (4), the currents flowing through the secondary windings W12 and W22 can be made smaller than the currents flowing through the primary windings W11 and W21. Loss in the secondary winding W12, loss in the secondary winding W22, and loss between the secondary winding W12 and the secondary winding W22 can be reduced.

<Tenth Embodiment>
[Configuration of Cell Balance Circuit LL]
FIG. 13 is a circuit diagram of the cell balance circuit LL according to the tenth embodiment of the present invention. The cell balance circuit LL differs from the cell balance circuit KK according to the ninth embodiment of the present invention shown in FIG. 12 in that it includes a control unit 21 and a capacitor CD, and includes a buffer BUF1 and an inverter INV1 instead of the switch SW1. The difference is that a buffer BUF2 and an inverter INV2 are provided instead of the switch SW2. In the cell balance circuit LL, the same components as those of the cell balance circuit KK are denoted by the same reference numerals, and the description thereof is omitted.

  The control unit 21 is connected to the input terminal of the buffer BUF2 and the input terminal of the inverter INV2. One end of the primary winding W21 is connected to the output terminal of the buffer BUF2, and the other end of the primary winding W21 is connected to the output terminal of the inverter INV2. One end of the secondary battery BT2 is connected to the high potential side control terminal of the buffer BUF2 and the high potential side control terminal of the inverter INV2, and the low potential side control terminal of the buffer BUF2 and the low potential side control terminal of the inverter INV2 Are connected to the other end of the secondary battery BT2.

  Similarly to the buffer BUF2 and the inverter INV2, the buffer BUF1 and the inverter INV1 are connected to the control unit 21, the secondary battery BT1, and the primary winding W11. The control unit 21 is connected to the input terminal of the buffer BUF1 and the input terminal of the inverter INV1 via the capacitor CD.

[Operation of Cell Balance Circuit LL]
The control unit 21 outputs a control signal with a duty ratio of 50% when the secondary batteries BT1 and BT2 are charged and discharged. Since this control signal is input to the input terminals of the buffers BUF1 and BUF2 and the input terminals of the inverters INV1 and INV2, the buffers BUF1 and BUF2 and the inverters INV1 and INV2 are synchronously controlled.

  When the voltage level of the control signal is H level, in the buffers BUF1 and BUF2, the output terminal and the high potential side control terminal are conducted, and in the inverters INV1 and INV2, the output terminal and the low potential side control terminal are conducted. To do. According to this, one end of each of the secondary batteries BT1 and BT2 and one end of each of the primary windings W11 and W21 are connected, and the other end of each of the secondary batteries BT1 and BT2 and 1 The other ends of the secondary windings W11 and W21 are connected to each other, and the charging voltages of the secondary batteries BT1 and BT2 are applied to the primary windings W11 and W21, respectively.

  On the other hand, when the voltage level of the control signal is L level, in the buffers BUF1 and BUF2, the output terminal and the low-potential side control terminal are conducted, and in the inverters INV1 and INV2, the output terminal and the high-potential side control terminal are connected. Is conducted. According to this, one end of each of the secondary batteries BT1, BT2 and the other end of each of the primary windings W11, W21 are connected and the other end of each of the secondary batteries BT1, BT2, One ends of the primary windings W11 and W21 are connected to each other, and the charging voltages of the secondary batteries BT1 and BT2 are applied to the primary windings W11 and W21, respectively.

  As described above, similarly to the above-described cell balance circuit KK, a current corresponding to the relationship between the charging voltage of the secondary battery BT1 and the charging voltage of the secondary battery BT2 flows through the secondary batteries BT1 and BT2.

  Note that, when the voltage level of the control signal is H level and L level, the polarity of the voltage at one end with respect to the other end of the primary winding W11 is reversed and the other end of the primary winding W21 is reversed. The polarity of the voltage at one end with respect to is also reversed.

  According to the above cell balance circuit LL, in addition to the above-described effects that can be achieved by the cell balance circuit KK according to the ninth embodiment of the present invention shown in FIG. 12, the following effects can be achieved.

  In the cell balance circuit LL, since the duty ratio of the control signal output from the control unit 21 is 50%, the first period and the second period can be alternately provided at equal time. Here, the first period means that one end of each of the secondary batteries BT1 and BT2 and one end of each of the primary windings W11 and W21 are connected and the other of each of the secondary batteries BT1 and BT2. This is a period in which the end and the other ends of the primary windings W11 and W21 are connected. In addition, the second period means that one end of each of the secondary batteries BT1 and BT2 and the other end of each of the primary windings W11 and W21 are connected and the other of each of the secondary batteries BT1 and BT2. This is a period in which the end and one end of each of the primary windings W11 and W21 are connected. For this reason, each charging voltage of secondary battery BT1 and BT2 can be equalized more correctly.

  In the cell balance circuit LL, the duty ratio of the control signal output from the control unit 21 is 50% as described above. Therefore, the polarity of the voltage at one end with respect to the other end of the primary winding W11 and the polarity of the voltage at one end with respect to the other end of the primary winding W21 depend on the voltage level of the control signal. It will reverse periodically. Therefore, it is possible to prevent the transformers T1 and T2 from being saturated.

<Eleventh embodiment>
[Configuration of Cell Balance Circuit MM]
FIG. 14 is a circuit diagram of the cell balance circuit MM according to the eleventh embodiment of the present invention. The cell balance circuit MM is different from the cell balance circuit KK according to the ninth embodiment of the present invention shown in FIG. 12 in that it includes switches SW3 and SW4 and a DC source 31. In the cell balance circuit MM, the same components as those of the cell balance circuit KK are denoted by the same reference numerals, and the description thereof is omitted.

  The DC source 31 includes a high potential side terminal and a low potential side terminal, and outputs a DC voltage based on the potential of the low potential side terminal from the high potential side terminal. The DC source 31 is configured by a device that outputs a DC voltage, such as a capacitor or a DC power source.

  One end of the secondary winding W12 and one end of the secondary winding W22 are connected to the high potential side terminal of the DC source 31. The other end of the secondary winding W12 is connected to the low potential side terminal of the DC source 31 via the switch SW3, and the other end of the secondary winding W22 is connected via the switch SW4. These switches SW3 and SW4 are constituted by, for example, MOSFET, IGBT, or BJT.

[Operation of cell balance circuit MM]
Similarly to the cell balance circuit KK, the cell balance circuit MM is configured so that if the charge voltage of the secondary battery BT1 and the charge voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1, BT2, By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform. A specific operation of the cell balance circuit MM will be described below.

  The cell balance circuit MM performs synchronous control of the switch SW1 and the switch SW3 and synchronous control of the switch SW2 and the switch SW4 by a control unit (not shown) when the secondary batteries BT1 and BT2 are charged and discharged. When the switch SW1 is turned on, the charging voltage of the secondary battery BT1 is applied to the primary winding W11, and when the switch SW2 is turned on, the charging voltage of the secondary battery BT2 is applied to the primary winding W21. It will be.

  When the charging voltage of the secondary battery BT1 is applied to the primary winding W11, a magnetic flux is generated in the primary winding W11, and this magnetic flux passes through the secondary winding W12. An electromotive force similar to that shown in the above-described equation (1) is generated. The electromotive force generated in the secondary winding W12 changes according to the charging voltage of the secondary battery BT1.

Also in the secondary winding W22, similarly to the above-described secondary winding W12, when the charging voltage of the secondary battery BT2 is applied to the primary winding W21, a magnetic flux is generated, and this magnetic flux is converted into the secondary winding W22. Therefore, an electromotive force similar to that expressed by the above formula (1) is generated in the secondary winding W22. The electromotive force generated in the secondary winding W22 changes according to the charging voltage of the secondary battery BT2.

  Here, the switch SW3 is synchronously controlled with the switch SW1 as described above, and when the switch SW3 is turned on, the output voltage of the DC source 31 is applied to the secondary winding W12. For this reason, a current flows between the secondary winding W12 and the DC source 31 until the winding voltage of the secondary winding W12 and the output voltage of the DC source 31 become equal. As a result, the ratio between the charging voltage of the secondary battery BT1 and the output voltage of the DC source 31 becomes equal to the turn ratio between the primary winding W11 and the secondary winding W12.

  Further, the switch SW4 is synchronously controlled with the switch SW2 as described above, and when the switch SW4 is turned on, the output voltage of the DC source 31 is applied to the secondary winding W22. For this reason, a current flows between the secondary winding W22 and the DC source 31 until the winding voltage of the secondary winding W22 is equal to the output voltage of the DC source 31. As a result, the ratio between the charging voltage of the secondary battery BT2 and the output voltage of the DC source 31 becomes equal to the turns ratio of the primary winding W21 and the secondary winding W22.

  Here, as described above, the number of turns of the primary winding W11 is equal to the number of turns of the primary winding W21, and the number of turns of the secondary winding W12 is equal to the number of turns of the secondary winding W22. For this reason, the turns ratio between the primary winding W11 and the secondary winding W12 is equal to the turns ratio between the primary winding W21 and the secondary winding W22. Therefore, the ratio between the charging voltage of the secondary battery BT1 and the output voltage of the DC source 31 is equal to the ratio of the charging voltage of the secondary battery BT2 and the output voltage of the DC source 31. Therefore, the charging voltage of the secondary battery BT1 is equal to the charging voltage of the secondary battery BT2.

  According to the above cell balance circuit MM, the same effects as those described above that can be achieved by the cell balance circuit KK according to the ninth embodiment of the present invention shown in FIG. 12 can be obtained.

<Twelfth embodiment>
[Configuration of Cell Balance Circuit NN]
FIG. 15 is a circuit diagram of a cell balance circuit NN according to the twelfth embodiment of the present invention. The cell balance circuit NN is different from the cell balance circuit MM according to the eleventh embodiment of the present invention shown in FIG. 14 in that it includes control units 22 and 23, and includes a buffer BUF1 and an inverter INV1 instead of the switch SW1. The difference is that a buffer BUF2 and an inverter INV2 are provided instead of the switch SW2, a buffer BUF3 and an inverter INV3 are provided instead of the switch SW3, and a buffer BUF4 and an inverter INV4 are provided instead of the switch SW4. In the cell balance circuit NN, the same constituent elements as those of the cell balance circuit MM are denoted by the same reference numerals, and the description thereof is omitted.

  The control unit 22 is connected to the input terminal of the buffer BUF1 and the input terminal of the inverter INV1. One end of the primary winding W11 is connected to the output terminal of the buffer BUF1, and the other end of the primary winding W11 is connected to the output terminal of the inverter INV1. One end of the secondary battery BT1 is connected to the high potential side control terminal of the buffer BUF1 and the high potential side control terminal of the inverter INV1, and the low potential side control terminal of the buffer BUF1 and the low potential side control terminal of the inverter INV1 Are connected to the other end of the secondary battery BT1.

  Similarly to the buffer BUF1 and the inverter INV1, the buffer BUF2 and the inverter INV2 are connected to the control unit 23, the secondary battery BT2, and the primary winding W21.

  The control unit 22 is connected to the input terminal of the buffer BUF3 and the input terminal of the inverter INV3. One end of the secondary winding W12 is connected to the output terminal of the buffer BUF3, and the other end of the secondary winding W12 is connected to the output terminal of the inverter INV3. The high potential side control terminal of the buffer BUF3 and the high potential side control terminal of the inverter INV3 are connected to the high potential side terminal of the DC source 31, and the low potential side control terminal of the buffer BUF3 and the low potential side of the inverter INV3 The low potential side terminal of the direct current source 31 is connected to the control terminal.

  Similarly to the buffer BUF3 and the inverter INV3, the buffer BUF4 and the inverter INV4 are connected to the control unit 23, the secondary winding W22, and the DC source 31.

[Operation of Cell Balance Circuit NN]
Control unit 22 outputs a control signal having a duty ratio of 50% when secondary battery BT1 is charged and discharged. Since the control signal output from the control unit 22 is input to the input terminals of the buffers BUF1 and BUF3 and the input terminals of the inverters INV1 and INV3, the buffers BUF1 and BUF3 and the inverters INV1 and INV3 are controlled synchronously. Will be.

  When the voltage level of the control signal output from the control unit 22 is H level, in the buffer BUF1, the output terminal and the high potential side control terminal become conductive, and in the inverter INV1, the output terminal and the low potential side control terminal And conduct. According to this, one end of the secondary battery BT1 and one end of the primary winding W11 are connected, and the other end of the secondary battery BT1 and the other end of the primary winding W11 are connected. The charging voltage of the secondary battery BT1 is applied to the primary winding W11.

  On the other hand, when the voltage level of the control signal output from the control unit 22 is L level, in the buffer BUF1, the output terminal and the low-potential side control terminal become conductive, and in the inverter INV1, the output terminal and the high-potential side Conduction with the control terminal. According to this, one end of the secondary battery BT1 and the other end of the primary winding W11 are connected, and the other end of the secondary battery BT1 and one end of the primary winding W11 are connected. The charging voltage of the secondary battery BT1 is applied to the primary winding W11.

  Note that, when the voltage level of the control signal output from the control unit 22 is H level or L level, the polarity of the voltage at one end with respect to the other end of the primary winding W11 is inverted. For this reason, the polarity of the voltage at one end with respect to the other end of the secondary winding W12 is inverted between the case where the voltage level of the control signal output from the control unit 22 is the H level and the case where the voltage level is the L level.

  When the voltage level of the control signal output from the control unit 22 is H level, the output terminal and the high potential side control terminal are electrically connected in the buffer BUF3, and the output terminal and the low potential side are connected in the inverter INV3. Conduction with the control terminal. According to this, one end of the secondary winding W12 and the high potential side terminal of the DC source 31 are connected, and the other end of the secondary winding W12, the low potential side terminal of the DC source 31, Are connected, and the output voltage of the DC source 31 is applied to the secondary winding W12.

  On the other hand, when the voltage level of the control signal output from the control unit 22 is L level, in the buffer BUF3, the output terminal and the low potential side control terminal become conductive, and in the inverter INV3, the output terminal and the high potential side Conduction with the control terminal. According to this, one end of the secondary winding W12 and the low potential side terminal of the DC source 31 are connected, and the other end of the secondary winding W12, the high potential side terminal of the DC source 31, Are connected, and the output voltage of the DC source 31 is applied to the secondary winding W12.

  As described above, when the voltage level of the control signal output from the control unit 22 is H level or L level, the polarity of the voltage at one end with respect to the other end of the secondary winding W12 is Invert. However, when the voltage level of the control signal output from the control unit 22 is H level or L level, one end or the other end of the secondary winding W12 and the high potential side terminal or low potential of the DC source 31 are used. The connection with the side terminal is switched as described above. Therefore, even if the polarity of the voltage at one end with respect to the other end of the secondary winding W12 is inverted according to the voltage level of the control signal output from the control unit 22, one end of the secondary winding W12 and the other Of the ends, the higher potential is connected to the high potential side terminal of the DC source 31, and the lower potential is connected to the low potential side terminal of the DC source 31.

  Similarly to the control unit 22, the control unit 23 outputs a control signal having a duty ratio of 50% when the secondary battery BT2 is charged and discharged. Since the control signal output from the control unit 23 is input to the input terminals of the buffers BUF2 and BUF4 and the input terminals of the inverters INV2 and INV4, the buffers BUF2 and BUF4 and the inverters INV2 and INV4 are synchronously controlled. Will be.

  Each of the buffers BUF2 and BUF4 and the inverters INV2 and INV4 to which the control signal output from the control unit 23 is input to the input terminal includes the buffers BUF1 and BUF3 to which the control signal output from the control unit 22 is input to the input terminal and It operates in the same manner as each of the inverters INV1 and INV3.

  For this reason, the charging voltage of the secondary battery BT2 is applied to the primary winding W21, and the primary winding W21 depends on whether the voltage level of the control signal output from the control unit 23 is H level or L level. The polarity of the voltage at one end with respect to the other end is reversed. Therefore, the polarity of the voltage at one end with respect to the other end of the secondary winding W22 is inverted between the case where the voltage level of the control signal output from the control unit 23 is the H level and the case where the voltage level is the L level.

  Further, when the voltage level of the control signal output from the control unit 23 is H level or L level, one end or the other end of the secondary winding W22 and the high potential side terminal or low potential of the DC source 31 are used. The connection with the side terminal is switched as described above. Therefore, even if the polarity of the voltage at one end with respect to the other end of the secondary winding W22 is inverted as described above according to the voltage level of the control signal output from the control unit 23, the secondary winding W22 is reversed. Of the one end and the other end, the higher potential is connected to the high potential side terminal of the DC source 31, and the lower potential is connected to the low potential side terminal of the DC source 31.

  According to the above cell balance circuit NN, in addition to the above-described effects that can be achieved by the cell balance circuit MM according to the eleventh embodiment of the present invention shown in FIG. 14, the following effects can be achieved.

  In the cell balance circuit NN, the higher one of the one end and the other end of the secondary winding W12 is connected to the high potential side terminal of the DC source 31 regardless of the voltage level of the control signal output from the control unit 22. Then, the lower potential continues to be connected to the low potential side terminal of the DC source 31. For this reason, the voltage of the wiring between the secondary winding W12 and the direct current source 31 becomes direct current. Therefore, if it is alternating current, it is affected by the inductor component of the wiring, but since it is direct current, the influence of the inductor component of the wiring can be suppressed, and the wiring between the secondary winding W12 and the DC source 31 is lengthened. can do. Further, since the voltage of the wiring between the secondary winding W22 and the DC source 31 is also DC like the voltage of the wiring between the secondary winding W12 and the DC source 31, the secondary winding W22. And the DC source 31 can be made longer. According to the above, the design of the cell balance circuit NN can be facilitated.

  In the cell balance circuit NN, the voltage of the wiring between the secondary winding W12 and the DC source 31 and the voltage of the wiring between the secondary winding W22 and the DC source 31 are as described above. Becomes DC. Therefore, the buffers BUF1 and BUF3 and the inverters INV1 and INV3 are synchronously controlled. If the buffers BUF2 and BUF4 and the inverters INV2 and INV4 are synchronously controlled, the buffers BUF1 and BUF3 and the inverters INV1 and INV3, and the buffer BUF2, BUF4 and inverters INV2 and INV4 may be asynchronous control. Accordingly, the wiring delay between the control unit 22 and the respective input terminals of the buffers BUF1 and BUF3 and the inverters INV1 and INV3, and the connection between the control unit 23 and the buffers BUF2 and BUF4 and the respective input terminals of the inverters INV2 and INV4. Since it is not necessary to consider that the wiring delay in the wiring between them is equal, these wirings can be lengthened and the control by the control units 22 and 23 can be facilitated. Therefore, the design of the cell balance circuit NN can be further facilitated.

  Further, in the cell balance circuit NN, since the duty ratio of the control signal output from the control unit 22 is 50%, the first period and the second period can be alternately provided at an equal time, which is determined in advance. The connection between the secondary battery BT1 and the primary winding W11 can be switched every time. Here, in the first period, one end of the secondary battery BT1 and one end of the primary winding W11 are connected, and the other end of the secondary battery BT1 and the other end of the primary winding W11 are connected. And one end of the secondary winding W12 and the high potential side terminal of the DC source 31 are connected and the other end of the secondary winding W12 and the low potential side terminal of the DC source 31 are connected. That is. The second period is connected to one end of the secondary battery BT1 and the other end of the primary winding W11, and is connected to the other end of the secondary battery BT1 and one end of the primary winding W11. A period in which one end of the secondary winding W12 is connected to the low potential side terminal of the DC source 31 and the other end of the secondary winding W12 is connected to the high potential side terminal of the DC source 31. It is. In addition, since the duty ratio of the control signal output from the control unit 23 is also 50%, the secondary battery BT2 and the secondary battery BT2 each time a predetermined time elapses, similar to the secondary battery BT1 and the primary winding W11. The connection with the primary winding W21 can be switched. According to the above, each charging voltage of the secondary batteries BT1 and BT2 can be made more uniform.

  In the cell balance circuit NN, the duty ratio of the control signal output from the control unit 22 is 50% as described above. For this reason, the polarity of the voltage at one end with respect to the other end of the primary winding W11 is periodically inverted according to the voltage level of the control signal output from the control unit 22. Therefore, it is possible to prevent the transformer T1 from being saturated.

  In the cell balance circuit NN, the duty ratio of the control signal output from the control unit 23 is 50% as described above. For this reason, the polarity of the voltage at one end with respect to the other end of the primary winding W21 is also periodically inverted according to the voltage level of the control signal output from the control unit 23. Therefore, it is possible to prevent the transformer T2 from being saturated.

<13th Embodiment>
[Configuration of Cell Balance Circuit PP]
FIG. 16 is a circuit diagram of a cell balance circuit PP according to the thirteenth embodiment of the present invention. The cell balance circuit PP is different from the cell balance circuit NN according to the twelfth embodiment of the present invention shown in FIG. 15 in that switches SW5 and SW6 are provided instead of the buffer BUF3 and the inverter INV3, and the buffer BUF4 and the inverter INV4 The difference is that the switches SW7 and SW8 are provided instead, and the midpoints of the secondary windings W12 and W22 are used. In the cell balance circuit PP, the same components as those of the cell balance circuit NN are denoted by the same reference numerals, and the description thereof is omitted.

  One end of the secondary winding W12 is connected to the high potential side terminal of the DC source 31 via the switch SW5, and the other end of the secondary winding W12 is connected via the switch SW6, and the switch SW7. Is connected to one end of the secondary winding W22, and is connected to the other end of the secondary winding W22 via the switch SW8. The switches SW5 to SW8 are composed of, for example, a MOSFET, an IGBT, or a BJT. The midpoint of the secondary winding W12 and the midpoint of the secondary winding W22 are connected to the low potential side terminal of the DC source 31.

  In the following, for convenience, the secondary winding W12 includes a first secondary winding W121 and a second secondary winding W122, and one end of the first secondary winding W121 is connected to the secondary winding W12. The other end of the second secondary winding W122 is equal to the other end of the secondary winding W12, the other end of the first secondary winding W121 and one end of the second secondary winding W122. Is equal to the midpoint of the secondary winding W12. The secondary winding W22 includes a first secondary winding W221 and a second secondary winding W222, and one end of the first secondary winding W221 is equal to one end of the secondary winding W22. The other end of the second secondary winding W222 is equal to the other end of the secondary winding W22, and the other end of the first secondary winding W221 and one end of the second secondary winding W222 are secondary windings. Assume that it is equal to the midpoint of the line W22.

  Then, the number of turns of each of the first secondary windings W121 and W221 and the second secondary windings W122 and W222 is equal to each other and larger than the number of turns of each of the primary windings W11 and W21. .

[Operation of Cell Balance Circuit PP]
Similarly to the cell balance circuit NN, the cell balance circuit PP is configured so that if the charge voltage of the secondary battery BT1 and the charge voltage of the secondary battery BT2 are different during charging and discharging of the secondary batteries BT1 and BT2, these 2 By supplying current to the secondary batteries BT1 and BT2, the charging voltages of the secondary batteries BT1 and BT2 are made uniform. However, the operation on the secondary side of the transformers T1 and T2 is different from that of the cell balance circuit NN.

  Specifically, the primary side of the transformer T1 is buffered by the control unit 22 with a control signal having a duty ratio of 50% when the secondary battery BT1 is charged and discharged, as in the cell balance circuit NN. BUF1 and inverter INV1 are controlled synchronously. According to this, the electromotive force generated in the first secondary winding W121 and the second secondary winding W122 changes according to the charging voltage of the secondary battery BT1. In addition, the electromotive force generated in the first secondary winding W121 is equal to the electromotive force generated in the second secondary winding W122.

  On the other hand, for the secondary side of the transformer T1, the control unit 22 controls the switches SW5 and SW6 in synchronization with the buffer BUF1 and the inverter INV1 when the secondary battery BT1 is charged and discharged.

  More specifically, when the potential of one end of the first secondary winding W121 becomes higher than the potential of the other end due to the control of the buffer BUF1 and the inverter INV1, one end of the second secondary winding W122. Becomes higher than the potential at the other end. In this case, the switch SW5 is turned on and the switch SW6 is turned off. According to this, the higher potential side terminal of the direct current source 31 is the higher one of the one end of the first secondary winding W121 and the other end of the second secondary winding W122. One end of the first secondary winding W121 is connected, and the output voltage of the DC source 31 is applied to the first secondary winding W121.

  Further, when the potential of one end of the first secondary winding W121 becomes lower than the potential of the other end due to the control of the buffer BUF1 and the inverter INV1, the potential of one end of the second secondary winding W122 is changed to the other potential. It becomes lower than the potential at the edge. In this case, the switch SW5 is turned off and the switch SW6 is turned on. According to this, the higher potential side terminal of the direct current source 31 is the higher one of the one end of the first secondary winding W121 and the other end of the second secondary winding W122. The other end of the second secondary winding W122 is connected, and the output voltage of the DC source 31 is applied to the second secondary winding W122.

  According to the above, even if the polarity of the voltage at one end with respect to the other end of the secondary winding W12 is reversed according to the voltage level of the control signal output from the control unit 22, the one end of the secondary winding W12 is reversed. Of the other ends, the higher potential is connected to the high potential side terminal of the DC source 31, and the lower potential is connected to the low potential side terminal of the DC source 31.

  The buffer BUF2, the inverter INV2, and the switches SW7 and SW8 are also controlled by the control unit 23 in the same manner as the buffer BUF1, the inverter INV1, and the switches SW5 and SW6. According to this, even if the polarity of the voltage at one end with respect to the other end of the secondary winding W22 is reversed according to the voltage level of the control signal output from the control unit 23, one end of the secondary winding W22 Of the other ends, the higher potential is connected to the high potential side terminal of the DC source 31, and the lower potential is connected to the low potential side terminal of the DC source 31.

  According to the above cell balance circuit PP, the same effects as those described above that can be achieved by the cell balance circuit NN according to the twelfth embodiment of the present invention shown in FIG. 15 can be obtained.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made without departing from the gist of the present invention.

  For example, in the above-described embodiment, the full-bridge type circuit, the half-bridge type circuit, the forward type circuit, the push-pull type circuit, and the active clamp type forward type circuit are shown as the non-resonant type converter. However, the present invention is not limited to this, and other non-resonant converters such as flyback circuits can also be applied.

  Moreover, although the above-mentioned embodiment demonstrated the case where two secondary batteries were connected in series, it is not restricted to this. For example, the cell balance circuit of the present invention can be applied to a case where four secondary batteries are connected in series or a case where five secondary batteries are connected in series.

  Moreover, in the above-mentioned embodiment, although the cell balance circuit and the secondary battery were provided separately, you may provide not only this but integrally.

  In the first to eighth embodiments described above, the first winding Wa and the second winding Wb are wound around the same iron core. It may not be, or may be wound around different iron cores. In the ninth to thirteenth embodiments described above, the transformer T1 and the transformer T2 each have an iron core that is separated from each other. However, the present invention is not limited to this. For example, the transformer T1 and the transformer T2 may have no iron core.

DESCRIPTION OF SYMBOLS 1; Cell balance apparatus 21, 22, 23; Control part 31; DC source AA, AB, BB, CC, DD, EE, FF, GG, HH, JJ, KK, LL, MM, NN, PP; Cell balance circuit BT1 to BT3, BTn, BT (n + 1); secondary battery BUF1 to BUF4; buffer INV1 to INV4; inverter Q1 to Q8; switch elements SW1 to SW8, Sa, Sb, Sc, Sd; switch T, T1, T2; Wa; first winding Wb; second winding W11, W21; primary winding W12, W22; secondary winding W121, W221; first secondary winding W122, W222; second secondary Winding

Claims (5)

First secondary battery, a cell balance unit to equalize the respective charging voltage of the second secondary battery, and a third secondary battery,
A first cell balance circuit for equalizing respective charging voltages of the first secondary battery and the second secondary battery;
A second cell balance circuit for equalizing respective charging voltages of the second secondary battery and the third secondary battery,
The first cell balance circuit includes:
A first transformer having a first winding provided in a pair with the first secondary battery, and a second winding provided in a pair with the second secondary battery;
A first switching means the charging voltage of the first secondary battery that controls whether to apply to the first winding, comprising a,
The first switching means includes a first switch, a second switch, a third switch, and a fourth switch, and forms a non-resonant circuit,
The other end of the first winding and one end of the second winding are connected to the other end of the first secondary battery and to one end of the second secondary battery. ,
One end of the first winding is provided so as to be connectable to one end of the first secondary battery via the first switch, and the second secondary battery via the second switch. Provided to be connected to the other end of the
The other end of the second winding is provided so as to be connectable to one end of the first secondary battery via the third switch, and the second secondary via the fourth switch. Connected to the other end of the battery,
The first switching means includes the first switch and the fourth switch, the second switch and the third switch, the first secondary battery and the second secondary battery. Alternately during charging and discharging ,
The second cell balance circuit includes:
A second transformer having a third winding provided in a pair with the second secondary battery and a fourth winding provided in a pair with the third secondary battery;
A second switching means for controlling whether or not to apply a charging voltage of the second secondary battery to the third winding;
The second switching means includes a fifth switch, a sixth switch, a seventh switch, and an eighth switch, and forms a non-resonant circuit,
The other end of the third winding and one end of the fourth winding are connected to the other end of the second secondary battery and to one end of the third secondary battery. ,
One end of the third winding is provided so as to be connectable to one end of the second secondary battery via the fifth switch, and the third secondary battery via the sixth switch. Provided to be connected to the other end of the
The other end of the fourth winding is provided so as to be connectable to one end of the second secondary battery via the seventh switch, and the third secondary via the eighth switch. Connected to the other end of the battery,
The second switching means includes the fifth switch and the eighth switch, the sixth switch and the seventh switch, the second secondary battery and the third secondary battery. A cell balance device that is alternately turned on during charging and discharging . 2. The cell balance device according to claim 1, wherein the number of turns of the first winding, the number of turns of the second winding, and the number of turns of the third winding are equal. The first cell balance circuit is provided integrally with the first secondary battery ,
The second cell balancing circuit, the cell balancing apparatus according to claim 1 or 2, characterized in Rukoto provided integrally with the second secondary battery. The first winding and the second winding, and the second winding and the third winding are wound around an iron core, respectively. The cell balance apparatus in any one. Before SL first switch, and the switching of the second switch, the third switch, and said fourth switch,
Switching of the fifth switch, the sixth switch, the seventh switch, and the eighth switch;
Cell balance device according to claim 1, characterized in that it is asynchronous 4.

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